Knowra Cranial nerves Cranial nerves Cranial nerves are twelve pairs of nerves that arise directly from the brain or brainstem. They carry sensory, motor, and autonomic signals between the central nervous system and the head, neck, and some internal organs.
Cranial nerve nuclei : Groups of neurons in the brainstem that give rise to or receive fibers from cranial nerves. Most cranial nerves connect to the brainstem through specific nuclei.
Sensory nervous system : The neural pathways that detect stimuli and convey information to the central nervous system. Sensory cranial nerves transmit information such as vision, hearing, taste, and facial touch.
Cranial nerve examination : A bedside assessment of sensory and motor functions associated with the twelve cranial nerves. Testing the nerves individually can reveal which pathways or brain regions are impaired.
Spinal nerves : Thirty-one pairs of nerves that emerge from the spinal cord and connect it with the trunk and limbs. Unlike cranial nerves, spinal nerves arise from the spinal cord and mostly serve the body below the head.
Cranial nerve classification : A system that describes cranial nerves by number, name, function, and fiber type. Classification distinguishes sensory, motor, and mixed nerves across the twelve pairs.
Motor nervous system : The neural pathways that carry commands from the central nervous system to muscles and glands. Motor cranial nerves drive eye, facial, tongue, throat, and shoulder movements.
Bell's palsy : An acute peripheral weakness or paralysis of facial muscles, usually affecting one side of the face. It illustrates how dysfunction of cranial nerve VII affects facial movement.
Cervical plexus : A network formed by the anterior rami of the first four cervical spinal nerves. Its nerves supply parts of the neck and head, areas also served by cranial nerves.
Cranial nerve numbering : The convention that numbers cranial nerves I through XII from anterior to posterior. The numbering follows the nerves’ approximate front-to-back order of attachment to the brain.
Parasympathetic nervous system : The autonomic division that supports functions such as digestion, gland secretion, and pupil constriction. Four cranial nerves deliver parasympathetic signals to the head and thoracic and abdominal organs.
Show all 20